This application relates generally to a gas turbine engine, and more specifically to a coupling system which prevents rotation between components of the gas turbine engine.
A gas turbine engine typically includes a compressor which compresses air and delivers the air into a combustion section. In the combustion section air is mixed with fuel and combusted. Products of this combustion pass downstream over a turbine section. In one type of gas turbine engine, there are both low pressure and high pressure compressors, and low pressure and high pressure turbines. A “coupling stack” may attach the low pressure turbine to the low pressure compressor, such that the low pressure turbine drives the low pressure compressor to rotate. A tie-bolt may connect the two, and extends along a center line axis of the gas turbine engine. The coupling stack may also include a spanner nut, and a tab lock to connect the components.
During assembly, the tie-bolt may be stretched by a tool to provide a high amount of preload pressure, or tension, to the tie-bolt. When the tool is released, the tension on the tie-bolt provides compression throughout the coupling stack. The preload pressure provides enough force throughout the coupling stack to control relative movement between the components of the coupling stack. However, during operation, vibrations may cause the components to become unspooled, or loosened, such that the components may rotate relative to each other. Unspooling between components can cause a loss of preload pressure within the coupling stack.
Furthermore, the work area within the gas turbine engine for many components is at a small diameter and a great distance from a mechanic, and in a somewhat covered location, resulting in blind assembly.